Vanadium-based frit materials, and/or methods of making the same

ABSTRACT

Certain example embodiments relate to improved seals for glass articles. Certain example embodiments relate to a composition used for sealing an insulted glass unit. In certain example embodiments the composition includes vanadium oxide, barium oxide, zinc oxide, and at least one additional additive. For instance, another additive that is a different metal oxide or different metal chloride may be provided. In certain example embodiments, a vacuum insulated glass unit includes first and second glass substrates that are sealed together with a seal that includes the above-described composition.

FIELD OF THE INVENTION

Certain example embodiments of this invention relate to improved fritmaterials for glass articles (e.g., for use in vacuum insulated glass orVIG units), and/or methods of making the same, as well as articlesincluding such improved frit materials and/or methods of making thesame. More particularly, certain example embodiments relate tovanadium-based frit materials having a reduced melting point, and/ormethods of making the same. In certain example embodiments, the improvedinsulated seals are used in connection with vacuum insulated glass (VIG)units, and/or a method is provided for sealing VIG units with theimproved seals.

BACKGROUND AND SUMMARY OF EXAMPLE EMBODIMENTS OF THE INVENTION

Vacuum IG units are known in the art. For example, see U.S. Pat. Nos.5,664,395, 5,657,607, and 5,902,652, the disclosures of which are allhereby incorporated herein by reference.

FIGS. 1-2 illustrate a conventional vacuum IG unit (vacuum IG unit orVIG unit). Vacuum IG unit 1 includes two spaced apart glass substrates 2and 3, which enclose an evacuated or low pressure space 6 there between.Glass sheets/substrates 2 and 3 are interconnected by peripheral or edgeseal of fused solder glass 4 and an array of support pillars or spacers5.

Pump out tube 8 is hermetically sealed by solder glass 9 to an apertureor hole 10 which passes from an interior surface of glass sheet 2 to thebottom of recess 11 in the exterior face of sheet 2. A vacuum isattached to pump out tube 8 so that the interior cavity betweensubstrates 2 and 3 can be evacuated to create a low pressure area orspace 6. After evacuation, tube 8 is melted to seal the vacuum. Recess11 retains sealed tube 8. Optionally, a chemical getter 12 may beincluded within recess 13.

Conventional vacuum IG units, with their fused solder glass peripheralseals 4, have been manufactured as follows. Glass frit in a solution(ultimately to form solder glass edge seal 4) is initially depositedaround the periphery of substrate 2. The other substrate 3 is broughtdown over top of substrate 2 so as to sandwich spacers 5 and the glassfrit/solution there between. The entire assembly including sheets 2, 3,the spacers, and the seal material is then heated to a temperature ofapproximately 500° C., at which point the glass frit melts, wets thesurfaces of the glass sheets 2, 3, and ultimately forms hermeticperipheral or edge seal 4. This approximately 500° C. temperature ismaintained for from about one to eight hours. After formation of theperipheral/edge seal 4 and the seal around tube 8, the assembly iscooled to room temperature. It is noted that column 2 of U.S. Pat. No.5,664,395 states that a conventional vacuum IG processing temperature isapproximately 500° C. for one hour. Inventors Lenzen, Turner and Collinsof the '395 patent have stated that “the edge seal process is currentlyquite slow: typically the temperature of the sample is increased at 200°C. per hour, and held for one hour at a constant value ranging from 430°C. and 530° C. depending on the solder glass composition.” Afterformation of edge seal 4, a vacuum is drawn via the tube to form lowpressure space 6.

The composition of conventional edge seals are known in the art. See,for example, U.S. Pat. Nos. 3,837,866; 4,256,495; 4,743,302; 5,051,381;5,188,990; 5,336,644; 5,534,469; 7,425,518, and U.S. Publication No.2005/0233885, the disclosures of which are all hereby incorporatedherein by reference.

Unfortunately, the aforesaid high temperatures and long heating times ofthe entire assembly utilized in the formulation of edge seal 4 areundesirable. This is especially the case when it is desired to use aheat strengthened or tempered glass substrate(s) 2, 3 in the vacuum IGunit. As shown in FIGS. 3-4, tempered glass loses temper strength uponexposure to high temperatures as a function of heating time. Moreover,such high processing temperatures may adversely affect certain low-Ecoating(s) that may be applied to one or both of the glass substrates incertain instances.

FIG. 3 is a graph illustrating how fully thermally tempered plate glassloses original temper upon exposure to different temperatures fordifferent periods of time, where the original center tension stress is3,200 MU per inch. The x-axis in FIG. 3 is exponentially representativeof time in hours (from 1 to 1,000 hours), while the y-axis is indicativeof the percentage of original temper strength remaining after heatexposure. FIG. 4 is a graph similar to FIG. 3, except that the x-axis inFIG. 4 extends from zero to one hour exponentially.

Seven different curves are illustrated in FIG. 3, each indicative of adifferent temperature exposure in degrees Fahrenheit (° F.). Thedifferent curves/lines are 400° F. (across the top of the FIG. 3 graph),500° F., 600° F., 700° F., 800° F., 900° F., and 950° F. (the bottomcurve of the FIG. 3 graph). A temperature of 900° F. is equivalent toapproximately 482° C., which is within the range utilized for formingthe aforesaid conventional solder glass peripheral seal 4 in FIGS. 1-2.Thus, attention is drawn to the 900° F. curve in FIG. 3, labeled byreference number 18. As shown, only 20% of the original temper strengthremains after one hour at this temperature (900° F. or 482° C.). Such asignificant loss (i.e., 80% loss) of temper strength may be undesirable.

As seen in FIGS. 3-4, the percentage of remaining tempering strengthvaries based on the temperature that is exposed to the tempered glass.For example, at 900° F. only about 20% of the original temper strengthremains. When the temperature that the sheet is exposed to is reduced to800° F., about 428° C., the amount of strength remaining is about 70%.Finally, a reduction in temperature to about 600° F., about 315° C.,results in about 95% of the original temper strength of the sheetremaining. As will be appreciated, it is desirable to reduce any temperstrength losses as a result of exposing a tempered sheet of glass tohigh temperatures.

As noted above, the creation of VIG units includes the creation of ahermetic seal that can withstand the pressure applied from the vacuumcreated on inside of the unit. As also discussed above, the creation ofthe seal may conventionally involve temperatures of at or above 500° C.These temperatures are required in order to obtain a high enoughtemperature in order for the frit material used for the seal to melt andform the required seal for the VIG units. As shown above, such atemperature can result in a strength reduction for VIG units usingtempered glass.

One conventional solution to sealing glass substrates together is to usean epoxy. However, in the case of VIG units, epoxy compositions may beinsufficient to hold a seal on a vacuum. Furthermore, epoxies may besusceptible to environmental factors that may further reduce theireffectiveness when applied to VIG units.

Another conventional solution is to use a frit solution that containslead. As is known, lead has a relatively low melting point. Accordingly,temperatures for sealing the VIG units may not need to be as high forother frit materials, and thus the tempering strength of tempered glasssubstrates may not be reduced by the same amount required for other fritbased materials. However, while lead based frits may resolve the abovestructural issues, the usage of lead in the frit may create newproblems. Specifically, the health consequences to the population forproducts that contain lead. Additionally, certain countries (e.g., inthe European Union) may impose strict requirements on the amount of leadthat can be contained in a given product. Indeed, some countries (orcustomers) may require products that are completely lead-free.

Thus, it will be appreciated that techniques for creating improved sealsfor glass articles are continuously sought after. It also will beappreciated that there exists a need in the art for improved seals andthe like that can be integrated with tempered glass units, such as, forexample, VIG units. The seals may be designed to allow for reducedtemperature sealing such that annealed or tempered glass can be sealedwithout detrimental impact on the properties of the glass.

In certain example embodiments, a frit material having a composition isprovided. The fit material may include vanadium oxide between about 50%and 60% weight, barium oxide between about 27% and 33% weight, and zincoxide between about 9% and 12% weight. In certain example embodiments,the frit material may also include at least one additive selected fromamong: Ta₂O₅, Ti₂O₃, SrCl₂, GeO₂, CuO, AgO, Nb₂O₅, B₂O₃, MgO, SiO₂,TeO₂, Tl₂O₃, Y₂O₃, SnF2, SnO2, CuCl, SnCl₂, CeO₂, AgCl, In₂O₃, SnO, SrO,MgO, and Al₂O₃.

In certain example embodiments, a vacuum insulted glass (VIG) unit isprovided. The VIG unit may include first and second substantiallyparallel, spaced apart glass substrates. An edge seal is provided arounda periphery of the first and second substrates to form a hermetic sealthere between and at least partially defining a gap between the firstand second substrates. The gap defined between the first and secondsubstrates is at a pressure less than atmospheric. The edge sealincludes a frit material, e.g., as made from a base composition asdescribed herein.

In certain example embodiments, a method of making a frit material isprovided. A base composition is provided to a holder. The basecomposition includes vanadium oxide between about 50% and 60% weight,barium oxide between about 27% and 33% weight, zinc oxide between about9% and 12% weight, and at least one additive selected from among: Ta₂O₅,Ti₂O₃, SrCl₂, GeO₂, CuO, AgO, Nb₂O₅, B₂O₃, MgO, SiO₂, TeO2, Tl2O3, Y2O3,SnF2, SnO2, CuCl, SnCl2, CeO2, AgCl, In2O3, SnO, SrO, MgO, and Al₂O₃.The base composition is melted. The base composition is cooled orallowed to cool, forming an intermediate glass article. The intermediateglass article is ground to make the frit material.

In certain example embodiments, a method of making a vacuum insulatedglass (VIG) unit is provided. First and second glass substrates insubstantially parallel, spaced apart relation to one another areprovided. The first and second glass substrates using a frit materialare sealed together, with a gap being defined between the first andsecond substrates. The sealing being performed by melting the fritmaterial at a temperature of no more than about 375 degrees C. Where thefrit material has been formed from a base composition including vanadiumoxide between about 50% and 60% weight, barium oxide between about 27%and 33% weight, zinc oxide between about 9% and 12% weight, and at leastone oxide or chloride-base additive.

In certain example embodiments, a frit material having a composition isprovided. The frit material may include vanadium oxide between about 50%and 60% weight, barium oxide between about 27% and 33% weight, and zincoxide between about 9% and 12% weight. The frit material includes atleast a first and second additive selected from among SiO₂, SnCl₂,Al₂O₃, and TeO₂.

Certain example embodiments may include at least two additives. Forexample SnCl2 and SiO2. Certain example embodiments may include three orfour additives selected from among SiO₂, SnCl₂, Al₂O₃, and TeO₂.

The features, aspects, advantages, and example embodiments describedherein may be combined in any suitable combination or sub-combination torealize yet further embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features and advantages may be better and morecompletely understood by reference to the following detailed descriptionof exemplary illustrative embodiments in conjunction with the drawings,of which:

FIG. 1 is a cross-sectional view of a conventional vacuum IG unit;

FIG. 2 is a top plan view of the bottom substrate, edge seal, andspacers of the FIG. 1 vacuum IG unit taken along the section lineillustrated in FIG. 1;

FIG. 3 is a graph correlating time (hours) versus percent temperingstrength remaining, illustrating the loss of original temper strengthfor a thermally tempered sheet of glass after exposure to differenttemperatures for different periods of time;

FIG. 4 is a graph correlating time versus percent tempering strengthremaining similar to that of FIG. 3, except that a smaller time periodis provided on the x-axis;

FIG. 5 is cross-sectional view of a vacuum insulated glass unitaccording to certain example embodiments;

FIG. 6 is a flowchart illustrating a process for making a vacuuminsulated glass unit with a frit material according to certain exampleembodiments;

FIGS. 7A-7D are graphs summarizing properties of compositions accordingto certain example embodiments;

FIGS. 8A-8C are graphs summarizing the quality of compositions accordingto certain exemplary embodiments;

FIG. 9 is a graph showing results when additional elements are added tocompositions according to certain example embodiments;

FIGS. 10A-10C show graphs summarizing impacts of additives being addedto vanadium based frits according to certain example embodiments; and

FIGS. 11A-11C show graphs summarizing absorption in the visible andinfrared wavelengths for vanadium based frits according to certainexample embodiments.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS OF THE INVENTION

The following description is provided in relation to several exampleembodiments which may share common characteristics, features, etc. It isto be understood that one or more features of any one embodiment may becombinable with one or more features of other embodiments. In addition,single features or a combination of features may constitute anadditional embodiment(s).

Certain example embodiments may relate to glass units (e.g., VIG units)that include two glass substrates sealed with an improved seal, e.g., ofor including a vanadium-based frit material. In certain exampleembodiments an improved seal may include the following materials:vanadium oxide, barium oxide, and zinc oxide. In addition, certainexample embodiments may include one or more of the following compounds:Ta₂O₅, Ti₂O₃, SrCl₂, GeO₂, CuO, AgO, Nb₂O₅, B₂O₃, MgO, SiO₂, TeO2,Tl2O3, Y2O3, SnF2, SnO2, CuCl, SnCl2, CeO2, AgCl, In2O3, SnO, SrO, MgO,and Al₂O₃.

FIG. 5 is cross-sectional view of a vacuum insulated glass unitaccording to certain example embodiments. VIG unit 500 may include firstand second glass substrates 502 a and 502 b that are spaced apart anddefine a space therebetween. The glass substrates 502 a and 502 b may beconnected via an improved seal 504, of or including a vanadium-basedfrit. Support pillars 506 may help maintain the first and secondsubstrates 502 a and 502 b in substantially parallel spaced apartrelation to one another. It will be appreciated that the CTE of theimproved seal 504 and the glass substrates 502 a and 502 b maysubstantially match one another. This may be advantageous in terms ofreducing the likelihood of the glass cracking, etc. Although FIG. 5 isdescribed in relation to a VIG unit, it will be appreciated that theimproved seal 504, of or including a vanadium-based frit may be used inconnection with other articles and/or arrangements including, forexample, insulating glass (IG) units and/or other articles.

FIG. 6 is a flowchart illustrating a process for preparing a fritmaterial to be used in making a vacuum insulated glass unit according tocertain example embodiments. In step 600, base compounds are combinedand disposed into an appropriate container (e.g., a heat resistantcontainer such as, for example, a ceramic container). In step 602, thecombined compound is melted. Preferably, the temperature to melt thecombined material may be at least 1000° C. In certain exemplaryembodiments, the combined compound is melted at 1000° C. for between 30to 60 minutes. In certain exemplary embodiments, the combined compoundis melted at 1100° C. for 60 minutes. In certain exemplary embodiments,the combined compound is melted at 1200° C. for 60 minutes. In certainexemplary embodiments, the melting temperature is a cycle that includes500° C. for 15 minutes, 550° C. for 15 minutes, 600° C. for 15 minutes,and a ramp up to 1000° C. for 60 minutes.

After the combined compounds are melted, the material may be cooled instep 604, e.g., to form a glass sheet. After cooling, the glass may becrushed or ground into fine particulates in step 606. In certain exampleembodiments, the size of the particulates may be no larger than about100 mesh. Once the glass is ground into a powder, it may be disposedbetween the substrates in step 608. In certain example embodiments, thepowder may be dispensed as a paste with a binder. Heat may then beapplied in step 610 to the glass substrate and the powder. In certainexample embodiments, the heat may be between 300° C. and 400° C., ormore preferably between 325° C. and 375° C. It will be appreciated thatwhen heat of the above temperatures is applied to tempered glass thatthe tempered glass may lose a reduced amount of strength versus whenheat of in excess of 350° C. is applied to the tempered glass. Thus,certain example embodiments preferably involve a frit meltingtemperature of less than 500° C., more preferably less than 425° C., andsometimes less than 350° C.

In certain example embodiments, the combined compounds include thefollowing materials: vanadium oxide, barium oxide, and zinc oxide.

FIGS. 7A-7D show graphs summarizing properties of compositions accordingto certain example embodiments.

The table below corresponds to the data shown in FIG. 7A with thosecompositions with a melt quality of less than 4 (on a scale of 0 to 5)omitted from the table.

TABLE 1 Normalized Moles of Batch Composition V₂O₅ BaO ZnO BaO/ZnO Bi₂O₃B₂O₃ Tg(C.) Tx1(C.) Rating 43.66% 9.87% 46.47% 0.21 320 410 4 39.01%13.25% 37.37% .35 2.18% 8.20% 312 430 4 47.33% 12.96% 24.41% 0.53 9.95%5.53% 305 380 4 50.24% 23.38% 21.39% 1.33 320 425 4 51.54% 26.26% 16.46%1.60 5.75% 320 410 4.5

The melts shown in FIG. 7A were applied to a microscope glass slide witha temperature of 375° C. applied for 15 minutes. FIG. 7B shows a graphthat includes the crystallization temperature (first crystallizationpeak—Tx1—of the above table) of the above melts. According to certainexemplary embodiments, a preferred temperature for Tx1 may be betweenabout 375° C. and 425° C., preferably about 400° C.

FIG. 7C shows the transition glass temperatures, Tg, compared the abovemelts. The graph showing exemplary data shows that Tg values betweenabout 290 C and 335 C may be preferred for the above compositions.

FIG. 7D includes the above melts in a graph showing the melt qualityversus the barium/zinc ratio.

FIGS. 8A-8C show graphs that summarize the quality of compositionsaccording to certain exemplary embodiments. FIG. 8A summarizes the V₂O₅percentage used in certain exemplary compositions. FIG. 8B summarizesthe BaO percentage used in certain exemplary compositions. FIG. 8Csummarizes the ZnO percentage used in certain exemplary compositions. Asshown in the illustrative graphs, a vanadium percentage of between about51% and 53% may be preferable according to certain example embodiments.

Below, tables 2A-2C show exemplary compositions according to certainexample embodiments. Additionally, examples 7-15 in the tablescorrespond to graphs 8A-8C. For the compositions shown in the belowtables, BaCO₃ factor of 1.287027979 was used to convert to a BaOresulting compound.

TABLE 2A Weights of Batch Normalized Weight Composition WeightPercentage Weight for 25 grams Percentage Ex. V₂O₅ BaO ZnO Normal V₂O₅BaO ZnO V₂O₅ BaO ZnO 1 60 30 10 0.23 13.800 8.880 2.300 55.24 35.55 9.212 52.5 25 10 0.27 14.175 8.687 2.700 55.45 33.99 10.56 3 45 20 10 0.3113.950 7.980 3.100 55.73 31.88 12.39 4 45 10 20 0.32 14.400 4.118 6.40057.79 16.53 25.68 5 52.5 10 25 0.28 14.700 3.604 7.000 58.09 14.24 27.666 60 10 30 0.25 15.000 3.218 7.500 58.33 12.51 29.16 7 52.5 25 10 0.2412.600 7.722 2.400 55.45 33.99 10.56 8 57.5 25 10 0.25 14.375 8.0442.500 57.69 32.28 10.03 9 47.5 25 10 0.28 13.300 9.009 2.800 52.97 35.8811.15 10 52.5 27.5 10 0.26 13.650 9.202 2.600 53.63 36.15 10.22 11 57.527.5 10 0.25 14.375 8.848 2.500 55.88 34.40 9.72 12 47.5 27.5 10 0.2712.825 9.556 2.700 51.13 38.10 10.77 13 52.5 22.5 10 0.28 14.700 8.1082.800 57.40 31.66 10.93 14 57.5 22.5 10 0.26 14.950 7.529 2.600 59.6130.02 10.37 15 47.5 22.5 10 0.29 13.775 8.398 2.900 54.94 33.49 11.57

TABLE 2B Moles of Batch Normalized Moles Glass Ex. V₂O₅ BaO ZnO V₂O₅ BaOZnO Type 1 0.3037 0.1801 0.1132 50.87% 30.17% 18.95% amor- phous 20.3049 0.1722 0.1298 50.24% 28.38% 21.39% glassy 3 0.3064 0.1616 0.152249.41% 26.05% 24.54% amor- phous 4 0.3177 0.0838 0.3156 44.31% 11.68%44.01% amor- phous 5 0.3194 0.0722 0.3400 43.66% 9.87% 46.47% amor-phous 6 0.3207 0.0634 0.3584 43.19% 8.54% 48.27% amor- phous 7 0.30490.1722 0.1298 50.24% 28.38% 21.39% glassy 8 0.3172 0.1636 0.1233 52.51%27.08% 20.41% glassy 9 0.2912 0.1818 0.1370 47.74% 29.80% 22.46% glassy10 0.2949 0.1832 0.1255 48.85% 30.35% 20.80% glassy 11 0.3073 0.17430.1194 51.12% 29.00% 19.87% glassy 12 0.2811 0.1931 0.1323 46.35% 31.83%21.81% glassy 13 0.3156 0.1604 0.1344 51.70% 26.28% 22.01% glassy 140.3278 0.1521 0.1274 53.97% 25.05% 20.98% glassy 15 0.3021 0.1697 0.142149.20% 27.65% 23.15% glassy

The rating shown in Table 2C is based off of deposing the groundcomposition on a microscope glass slide and heating the composition atabout 375° C. for between 10 and 30 minutes.

TABLE 2C Example Tg (C. °) Tx2 (C. °) Tx2 (C. °) Tx1 − Tg Rating 1 280330 540 50 0.0 2 320 425 525 105 4.0 3 280 430 550 150 0.0 4 280 320 36540 0.0 5 320 410 560 90 4.0 6 285 425 560 140 0.0 7 315 390 530 75 4.5 8295, 325 415 535 90 5.0 9 320 420 525 100 4.5 10 325 410 540 85 4.5 11315 395 530 80 4.5 12 330 415 560 85 4.0 13 315 400 530 85 5.0 14 305395 530 90 4.0 15 320 395 525 75 4.5

FIG. 9 shows a graph with results of adding additional elements (e.g.,Bi₂O₃ and B₂O₃) to a vanadium based frit. Corresponding data shown inFIG. 9 is also displayed below in Table 3.

TABLE 3 Ex. V2O5 BaO ZnO Bi2O3 B2O3 Tg(C.) Tx1(C.) DSC Responses 165.39% 14.87% 12.46% 0.00% 7.28% 320 430 medium weak 2 60.96% 13.86%11.61% 0.00% 13.57% 240 415 very weak 3 69.71% 15.85% 13.28% 1.16% 0.00%315 405 strong peaks 4 64.69% 14.71% 12.32% 1.08% 7.20% 325 440 veryweak 5 68.91% 15.67% 13.13% 2.29% 0.00% 320 410 medium weak 6 64.00%14.56% 12.19% 2.13% 7.12% 320 425 very weak 7 59.74% 13.59% 11.38% 1.99%13.30% 315 410 very weak 8 60.34% 13.72% 11.49% 1.00% 13.43% 315 400very weak 9 70.53% 16.04% 13.43% 0.00% 0.00% 315 380 strong peaks

In certain example embodiments, a strong DSC response may correspond toa good remelt quality. In certain example embodiments, the addition ofbismuth in concentrations of between about 0% and 3% may result inincreased remelt flow quality.

In certain example embodiments, a frit that includes V₂O₅, BaO, and ZnOmay further include one or more additives. In certain exampleembodiments, the additives may be between about 0.5% and 15% weight.According to certain example embodiments, the additives may be added toa base composition that includes between about 50% and 60% weight V₂O₅,27% and 33% weight BaO, and 9% and 12% weight ZnO.

Below, Tables 4A-4D show results of including additives to the basecomposition of V₂O₅, BaO, and ZnO. Table 4D shows the melt quality on ascale of about 0 to 5 for each of the compositions. FIGS. 10A-10C showgraphs corresponding to the data shown in the below tables. A BaCO3factor of 1.2870 was used to form the BaO used for the followingexamples.

TABLE 4A Weights (gm) Normalized Weights Ex V2O5 BaO ZnO Additive TypeAmount V2O5 BaO ZnO Additive 1 52.5 22.5 10 TeO2 2 14.175 7.819 2.7000.540 2 52.5 22.5 10 TeO2 4 13.650 7.529 2.600 1.040 3 52.5 22.5 10Ta2O5 5 13.650 7.529 2.600 1.300 4 52.5 22.5 10 Ta2O5 10 13.125 7.2402.500 2.500 5 52.5 22.5 10 Ti2O3 5 13.650 7.529 2.600 1.300 6 52.5 22.510 Ti2O3 10 13.125 7.240 2.500 2.500 7 52.5 22.5 10 SrCl2 2 14.175 7.8192.700 0.540 8 52.5 22.5 10 SrCl2 4 13.650 7.529 2.600 1.040 9 52.5 22.510 GeO2 1 14.175 7.819 2.700 0.270 10 52.5 22.5 10 GeO2 2 14.175 7.8192.700 0.540 11 52.5 22.5 10 CuO 1 14.175 7.819 2.700 0.270 12 52.5 22.510 CuO 2 14.175 7.819 2.700 0.540 13 52.5 22.5 10 AgO 1.5 14.175 7.8192.700 0.405 14 52.5 22.5 10 AgO 3 14.175 7.819 2.700 0.810 15 52.5 22.510 Nb2O5 3 14.175 7.819 2.700 0.810 16 52.5 22.5 10 Nb2O5 6 13.650 7.5292.600 1.560 17 52.5 22.5 10 B2O3 .8 14.175 7.819 2.700 0.216 18 52.522.5 10 B2O3 1.6 14.175 7.819 2.700 0.432

TABLE 4B Moles of Batch Composition Normalized Weight Percentage Addi-Ex V2O5 BaO ZnO Additive V2O5 BaO ZnO tive 1 56.17 30.99 10.70 2.140.309 0.157 0.131 0.013 2 55.00 30.34 10.48 4.19 0.302 0.154 0.129 0.0263 54.43 30.02 10.37 5.18 0.299 0.152 0.127 0.012 4 51.75 28.54 9.86 9.860.285 0.145 0.121 0.022 5 54.43 30.02 10.37 5.18 0.299 0.152 0.127 0.0116 51.75 28.54 9.86 9.86 0.285 0.145 0.121 0.022 7 56.17 30.99 10.70 2.140.309 0.157 0.131 0.013 8 55.00 30.34 10.48 4.19 0.302 0.154 0.129 0.0269 56.78 31.32 10.82 1.08 0.312 0.159 0.133 0.010 10 56.17 30.99 10.702.14 0.309 0.157 0.131 0.020 11 56.78 31.32 10.82 1.08 0.312 0.159 0.1330.014 12 56.17 30.99 10.70 2.14 0.309 0.157 0.131 0.027 13 56.48 31.1510.76 1.61 0.311 0.158 0.132 0.013 14 55.58 30.66 10.59 3.18 0.306 0.1550.130 0.026 15 55.58 30.66 10.59 3.18 0.306 0.155 0.130 0.012 16 53.8729.71 10.26 6.16 0.296 0.151 0.126 0.023 17 56.91 31.39 10.84 0.87 0.3130.159 0.133 0.012 18 56.42 31.12 10.75 1.72 0.310 0.158 0.132 0.025

TABLE 4C Normalized Moles Ex V2O5 BaO ZnO Additive Tg (C.) (Tx1(C.)Tx2(C.) Tx1 − Tg 1 50.57% 25.71% 21.53% 2.20% 315 400 525 85 2 49.48%25.16% 21.07% 4.30% 315 420 530 105 3 50.68% 25.76% 21.58% 1.99% 320 450130 4 49.69% 25.26% 21.16% 3.90% 320 450 530 130 5 50.71% 25.78% 21.59%1.92% 305 390 495 85 6 49.75% 25.29% 21.18% 3.77% 295 390 470 95 750.56% 25.70% 21.53% 2.21% 315 405 530 90 8 49.47% 25.15% 21.06% 4.32%315 400 530 85 9 50.83% 25.84% 21.64% 1.68% 315 395 530 80 10 49.99%25.41% 21.28% 3.31% 315 400 530 85 11 50.56% 25.71% 21.53% 2.20% 315 385525 70 12 49.47% 25.15% 21.06% 4.31% 320 395 545 75 13 50.61% 25.73%21.55% 2.12% 305 390 525 85 14 49.55% 25.19% 21.10% 4.16% 300 380 80 1550.68% 25.76% 21.58% 1.98% 315 425 550 110 16 49.69% 25.26% 21.16% 3.89%325 440 465 115 17 50.66% 25.75% 21.57% 2.02% 315 410 540 95 18 49.66%25.25% 21.14% 3.95% 320 405 545 85

TABLE 4D Melt Quality @ Melt Quality at Example 375 C., 15 min 350 C.,15 min 1 5.0 4.0 2 4.5 4.0 3 4.5 2.0 4 5.0 2.0 5 4.5 4.5 6 5.0 5.0 75.5+ 5.0 8 5.0 4.5 9 4.5 4.5 10 4.5 4.5 11 4.5 2.0 12 4.0 2.0 13 4.0 5.014 3.5 4.0 15 4.5 2.0 16 5.0 2.0 17 4.0 4.5 18 3.5 2.0

In certain example embodiments, the molar composition of an addiviate toa base composition higher than is shown in tables 4A-4D. Table 5A showsadditives with an increased additive amount (on a % mole basis). Thebase composition used with the additive amount may be based on, forexample, the base composition shown in Row 1 of Tables 4A-4D. Theadditives shown in Table 5, in the selected quantities displayed, mayimprove melt quality when compared to the above base composition. A melttype of Glassy indicates that a “button” of the compound melted onto aglass plate, forming a homogenous glassy structure. Sinter indicatesthat the compound (in a powder form) fused together, but remained in apowder form.

TABLE 5 Melt Type Adhesion Additive (350 C. for to glass Example TypeAmount 20 minutes) substrate. 1 CuCl 4.00% Glassy No Stick 2 SnCl2 3.99%Glassy No Stick 3 SnCl2 5.99% Glassy, Slight Flow Slight stick 4 SiO26.02% More Glassy No Stick 5 Al2O3 6.00% Glassy No Stick 6 CeO2 4.00%Sinter No Stick 7 TeO2 3.99% Glassy Slight stick 8 TeO2 6.01% GlassySlight stick 9 Tl2O3 3.99% Glassy, Slight Flow No Stick 10 Tl2O3 6.01%Glassy, Slight Flow No Stick

Accordingly, in certain example embodiments, additives of a relativelyincreased amount (e.g., versus those shown in FIG. 4) may be added to abase composition. In certain example embodiments, the additives mayinclude, for example, CuCl, SnCl₂, SiO₂, Al₂O₃, and TeO₂. It will beappreciated that toxic nature of thallium oxide (Tl₂O₃) may preclude itsuse in certain instances.

In certain example embodiments, two or more additives may be included ina base compound. Table 6 shows the results of adding two additives to anexemplary base composition. Table 6 includes example melts at 375 and350. Additionally, 13 mm buttons of the exemplary compounds were testedon a glass plate. The structural strength of the resulting exemplarycompound are also shown in the far right column.

TABLE 6 Melt Melt Amount Amount Quality Quality 13 mm 1 (Mole 2 (Mole(375 C. (350 C. Button Ex Add 1 Add 2 %) %) 15-20 Min) 15-20 Min) 350 C.20 Min Strength 1 TeO2 Al2O3 3.01 3.01 4.5 5.5 glassy Fractures 2 TeO2Al2O3 2.99 5.01 5 4 glassy Fractures 3 TeO2 Al2O3 4.02 3.01 6 5.5 glassyFractures 4 TeO2 Al2O3 3.99 5.00 5 4.5 glassy Fractures 5 TeO2 Al2O35.01 2.99 4.5 4.5 glassy Fractures 6 TeO2 Al2O3 5.00 5.00 5 4.5 glassyFractures 7 TeO2 SiO₂ 3.01 3.00 5 5.5 glassy Fractures 8 TeO2 SiO₂ 2.995.02 5 4.5 glassy Fractures 9 TeO2 SiO₂ 4.00 2.99 5 4 glassy Fractures10 TeO2 SiO₂ 3.99 4.99 5 4.5 Less Fractures glassy 11 TeO2 SiO₂ 5.002.99 4.5 4.5 Less Hard glassy 12 TeO2 SiO₂ 5.00 4.99 4.5 4.5 Less Hardglassy 13 SnCl2 Al2O3 3.01 3.01 5 6 more Hard glassy 14 SnCl2 Al2O3 3.005.01 5 5.5 glassy Hard 15 SnCl2 Al2O3 4.01 3.01 4.5 6 glassy Hard 16SnCl2 Al2O3 4.00 4.99 5.5 6 glassy Hard 17 SnCl2 Al2O3 5.00 2.99 5.5 5.5glassy Fractures 18 SnCl2 Al2O3 5.00 5.00 5.5 5.5 more Hard glassy 19SnCl2 SiO2 3.00 3.00 4.5 4.5 glassy Hard 20 SnCl2 SiO2 3.00 4.99 5 6glassy Hard 21 SnCl2 SiO2 4.00 2.99 6 6 glassy Fractures 22 SnCl2 SiO24.01 4.99 5.5 5.5 glassy Fractures 23 SnCl2 SiO2 5.00 2.99 5 5.5 glassyHard 24 SnCl2 SiO2 5.00 4.99 5.5 5.5 glassy Fractures 25 Al2O3 SiO2 3.013.00 4.5 4 less Hard glassy 26 Al2O3 SiO2 2.99 4.99 5 5.5 less Hardglassy 27 Al2O3 SiO2 4.00 2.99 4.5 4.5 less Hard glassy 28 Al2O3 SiO24.00 4.99 5 4.5 less Hard glassy 29 Al2O3 SiO2 5.01 2.99 5 4.5 less Hardglassy 30 Al2O3 SiO2 5.01 4.99 4 2 less Hard glassy

Accordingly, certain example may include two additives similar to thosefound in examples 3, 16, and 21 as shown in Table 6 (e.g., TeO2 withSiO2, SnCl2 with Al2O3, and SnCl2 with SiO2). In certain exampleembodiments, the addition of two or more additives may have beneficialresults on an exemplary base composition. For example the addition ofSiO2 to another additive may increase the strength of the overall frit.Alternatively, or in addition, TeO2 combined with other additives mayincrease the melt flow and glass wetting qualities of the frit whencompared to a base frit.

In certain example embodiments, the combination of SnCl2 with SiO2and/or Al2O3 may result in an increase in structural strength for theresulting frit material.

In certain example embodiments, one or more additives may be added to abase composition where the amount is between 1% and 10% by weight orbetween about 1% and 6% normalized moles for a batch. In certain exampleembodiments, additives may be added in a smaller amount, for examplebetween about 0.1% and 1% by weight. In certain example embodiments abatch for a base composition (in grams) may include V₂O₅ at 52.5, BaO at22.5, ZnO at 10. In certain example embodiments, additives added to theabove base composition may include: 1) TeO2 at 3.85 gm and Al2O3 at 1.84gm; 2) SnCl2 at 4.65 gm and Al2O3 at 3.12 gm; 3) SnCl2 at 4.55 gm andSiO2 at 1.08 gm. Correspondingly, the additives may then have anormalize weight percentage of: 1) TeO2 at 1.00 and Al2O3 at 0.48; 2)SnCl2 at 1.21 and Al2O3 at 0.81; 3) SnCl2 at 1.18 and SiO2 at 0.28.These examples may correspond to examples 3, 16, and 21 in the abovetable 6.

FIGS. 11A-11C show graphs illustrating absorption in the visible andinfrared wavelengths for vanadium based fits according to certainexample embodiments. As shown in the graphs, example vanadium basedfrits may have absorption of at least 90% across a substantial breath ofthe visible and IR spectrum. In certain example embodiments theabsorption may be about 95%. As discussed in co-pending application Ser.No. 12/929,874 entitled “IMPROVED FRIT MATERIALS AND/OR METHOD OF MAKINGVACUUM INSULATING GLASS UNITS INCLUDING THE SAME”, the entire contentsof which are incorporated herein by reference, frit materials with highvisible/IR absorption may be advantageous.

FIG. 11A shows the absorption properties of a vanadium based frit withTeO₂ and Al₂O₃ used as additives (e.g., Ex. 3 of Table 6). FIG. 11Bshows the absorption properties of a vanadium based frit with SnCl₂ andAl₂O₃ used as additives (e.g., Ex. 16 of Table 6). FIG. 11C shows theabsorption properties of a vanadium based frit with SnCl₂ and SiO₂ usedas additives (e.g., Ex. 21 of Table 6).

In certain example embodiments, the application of IR energy to a fritmaterial may be based on a heating profile where the IR energy appliedto the fit varies over time. Exemplary heating profiles may be found inco-pending application Ser. No. 12/929,874, the entire contents of whichare incorporated herein by reference.

In certain example embodiments, a base composition may be augmented by 3or 4 additives. For example, a batch for a base composition (in grams)may include V₂O₅ at 52.5, BaO at 22.5, ZnO at 10. Accordingly, threeand/or more additives from among TeO2, SnCl2, Al2O3, and SiO2 may beselected to augment the base composition. The ranges (in grams) for theadditives may vary between 0 to 7.5 grams per additive. Thus, on anormalized molar percentage the above additives may be included atbetween 0% and 6%. Thus, the normalized molar percentage of a basecomposition may be V₂O₅ at between about 43% and 50%, BaO between about22% and 26%, ZnO between about 18% and 22%. In certain exampleembodiments, additives (on a normalized molar basis) of TeO2 at around2%, SnCl2 around 2%, Al2O3 around 2%, and SiO2 around 4% may be added tothe base composition.

The techniques, compositions, etc disclosed herein may be used othermethods and/or systems for forming a VIG unit. For example, a vanadiumbased frit may be used to form an edge seal of a VIG unit. Systems,apparatuses, and/or methods used for creating a VIG unit may bedescribed in co-pending application Ser. No. 12/929,876 entitled“LOCALIZED HEATING TECHNIQUES INCORPORATING TUNABLE INFRARED ELEMENT(S)FOR VACUUM INSULATING GLASS UNITS, AND/OR APPARATUSES FOR THE SAME”, theentire contents of which are hereby incorporated by reference.

It will be appreciated by those skilled in the art that CTE adjustmentsmay be carried out on the overall frit material (e.g., the compound) forthe wetting and bonding properties of the frit to cooperate with anunderlying substrate (e.g., a glass substrate).

It will be appreciated that one or more metal oxide, chloride, and/orfluoride additives may be used as additives in different embodiments ofthis invention. Furthermore, in certain example implementations, themetal oxide, chloride, and/or fluoride additives may be stoichiometricor sub-stoichiometric.

As used herein, the terms “on,” “supported by,” and the like should notbe interpreted to mean that two elements are directly adjacent to oneanother unless explicitly stated. In other words, a first layer may besaid to be “on” or “supported by” a second layer, even if there are oneor more layers there between.

While the invention has been described in connection with what ispresently considered to be the most practical and preferred embodiment,it is to be understood that the invention is not to be limited to thedisclosed embodiment, but on the contrary, is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the appended claims.

What is claimed is:
 1. A vacuum insulted glass (VIG) window unit,comprising: first and second substantially parallel, spaced apart glasssubstrates in the window unit; an edge seal provided around a peripheryof the first and second substrates to form a hermetic seal therebetweenand at least partially defining a gap between the first and secondsubstrates, wherein the gap is provided at a pressure less thanatmospheric, and wherein a plurality of spacers are provided in the gapto space the substrates of the window unit apart, wherein the edge sealis formed from a frit material at least initially having a compositioncomprising: Ingredient Wt. % vanadium oxide ~50-60%, barium oxide~27-33%, zinc oxide  ~9-12%; and

a first additive comprising SrCl₂ constituting between about 1-8 wt. %.2. A vacuum insulted glass (VIG) window unit, comprising: first andsecond substantially parallel, spaced apart glass substrates in thewindow unit; an edge seal provided around a periphery of the first andsecond substrates to form a hermetic seal therebetween and at leastpartially defining a gap between the first and second substrates,wherein the gap is provided at a pressure less than atmospheric, andwherein a plurality of spacers are provided in the gap to space thesubstrates of the window unit apart, wherein the edge seal is formedfrom a frit material at least initially having a composition comprising:Ingredient Wt. % vanadium oxide ~50-60%, barium oxide ~27-33%, zincoxide  ~9-12%; and

a first additive comprising SnCl₂ and which constitutes between about1-8 wt. %.
 3. The VIG window unit of claim 2, wherein the frit materialfurther comprises a second additive comprising between about 1-8 wt. %of Al₂O₃.
 4. The VIG window unit of claim 2, wherein the frit materialfurther comprises a second additive comprising between about 0.5-5 wt. %of SiO₂.
 5. The VIG window unit of claim 1, wherein the frit materialhas a melting temperature less than about 400 degrees C.